More than 80 Native American tribes are challenging the official US census results and holding their own counts to increase their entitlement to federal money for healthcare and education.

Their action highlights the enormous increase in people claiming to be Native Americans for cultural and financial reasons, in contrast to the days when some tried to hide their tribal identities because of discrimination.

This month the department of housing and urban development confirmed that 86 Native American tribes were challenging the census assessments of their numbers. The larger the tribe, the greater its entitlement to federal money for healthcare and education.

The vast expansion of Native American gaming casinos is also feeding the argument about who qualifies as belonging to the ethnic group. Some on whose lands casinos have been built have become wealthy while others on less lucrative land live in poverty.

In 1910 there were officially 265,683 Native Americans, of whom more than half were full-bloods. The 1990 census gave a figure of 1.8 million, almost double that of 1980.

The 2000 figures, published in parts in the past year, show that 2.5 million now classify themselves as wholly and 1.6 million as partially Native American. Census estimates suggests that by last year the total had grown to 4.3 million.

So where have all the new Native Americans come from?

A census spokeswoman said 2000 was the first year people were free to classify themselves as part of a race, rather than by a single race.

A century ago great stigma was attached to being Native American because of prejudice and discrimination, but since the 1980s it has become fashionable to claim such ancestry, and Native Americans are technically one of the fastest-growing ethnic groups, though many have only one great-grandparent who was a full-blood Native American.

The supreme court ruled in 1978 that each tribe could set its own definition of membership. The Cherokee nation of Oklahoma, for instance, requires members to be descended from anyone listed on the 1906 federal roll after the liquidation of their reservation.

Yakimas require one-quarter blood, others require an eighth. Some give membership to all children of tribe members. Even with self-classification there are under-estimates, some activists say.

"It's a huge misnumbering," said David Laughing Horse Robinson, chairman of the Kawaiisu tribe in southern California, who stood for state governor in October.

"[The government] want to under-estimate because of the funding issue." Previous census-takers had not gone on to the reservations "because it was too dangerous - people didn't want to give up the information".

He believes that anyone with any trace of Indian blood should be able to claim to be Native American.

"Hitler said that if you had one drop of Jewish blood you were Jewish, so one drop of blood should give you the right to claim it [Native American identity]."

Sherman Alexie, the Indian - he prefers the term to Native American - novelist, poet and film-maker, recalls being invited to a round-table discussion on race with the then president Bill Clinton, who told him his grandmother had been part-Cherokee.

Later in the televised discussion he said: "The only time white folks talk to me about Indians is when they tell me their grandmothers were part-Cherokee." Mr Clinton enjoyed the joke.

Fergus Bordewich writes in his book Killing the White Man's Indian: "Each age has imagined its own Indian: untameable savage, child of nature, steward of the earth, the white man's ultimate victim.

"Imagining that we see the Indian, we have often seen little more than a warped reflection of ourselves; when Indians have stepped from the roles to which we have assig ned them, we have often seen nothing at all."

By any standard the latest figures are striking, considering the lack of political or cultural clout Native Americans have.

A total of 3.1 million American Indians and Alaskan natives claim membership of a specific tribe. The biggest is the Cherokee, with 697,400. Of those claiming tribal membership, 538,300 live on reservations or other trust lands, the biggest group being the 175,200 on Navajo lands in Arizona, New Mexico and Utah.

The 2000 census says 381,000 speak a native North American language, the most common being Navajo, which has 178,014 speakers.

Nowhere is the discrepancy between the past and the present greater than in California. During the 1848 gold rush, the Native American population was estimated at 150,000. By 1870 disease and slaughter had reduced it to 30,000. Now it is 683,000, the highest in the US.

But it has problems with definition. On the San Pasqual reservation in California "lineals", who live there but do not have enough blood to qualify for tribal membership, say they are excluded from tribal benefits. For instance, they got no compensation for the recent wildfire damage.

Now that the legal challenges are in place and others are being considered, the issue of identity may once again enter the national debate.

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